A common kind of liquid crystal display includes a frame, a display panel, and a main circuit board. A button circuit board includes a plurality of push buttons, which may for example be located in the frame below the display panel. The push buttons connect with a button circuit board inside the frame. In turn, the button circuit board is connected to the main circuit board. The push buttons are provided for users to adjust the characteristics of images shown on the display panel, such as brightness, contrast ratio etc.
Referring to FIG. 5, this shows an exploded, back view of main parts of a conventional liquid crystal display 1. The liquid crystal display 1 includes a frame 110, a display panel 120, a button-member 160, and a shield 140. A main circuit board (not visible) is electrically connected to the display panel 120 and the button member 160 by flexible printed circuit boards (not shown) respectively. A size of the shield 140 is substantially equal to that of the display panel 120. The shield 140 engages with the display panel 120, which cooperatively receive the main circuit board therebetween. The shield 140 provides screening to reduce electro-magnetic interference occurring in the main circuit board.
The frame 110 includes a plurality of through holes 112 in a lower beam thereof. An indicating light 114 is provided in the lower beam beside the through holes 112. The indicating light 114 shows a current state of the liquid crystal display 1. The button member 160 includes a button circuit board 162, a plurality of push buttons 164 disposed on the button circuit board 162, two screws 161, and two holes 163. The characteristics of images shown on the display panel 120 can be adjusted via the push buttons 164.
The shield 140 is made by molding a rectangular conductive metal plate, and includes a base 141, a first sidewall 142, a second sidewall 143, a third sidewall 144, and a fourth sidewall 145. The base 141 and the first, second, third, and fourth sidewalls 142, 143, 144, 145 cooperatively form a first receiving space (not labeled). A central protruding part 146 extends rearward from the base 141. A second receiving space (not labeled) is defined in the protruding part 146, and the main circuit board is received in the second receiving space.
Referring also to FIG. 6, this is an enlarged, isometric view of the shield 140. The fourth side wall 145 of the shield 140 includes a flange 147 bent downward from a middle portion of a main body thereof. The flange 147 is substantially perpendicular to the main body of the fourth side wall 145. The flange 147 includes two protrusions 148. Each protrusion 148 has a fixing hole 149 positioned corresponding to the hole 163 of the button circuit board 162 respectively.
When assembling the liquid crystal display 1, firstly, the display panel 120 and the circuit board are received in the first and second receiving spaces respectively. Then, the button member 160 is attached at the flange 147, with the protrusions 148 extending though the holes 163 respectively. Secondly, the button member 160 is fixed at the flange 147 by the screws 161 engaging in the fixing holes 149. Finally, the display panel 120 and the shield 140 are engaged together with the frame 110 then, received therebetween. In this position, the push buttons 164 protrude through the through holes 112.
The size of the shield 140 is substantially equal to that of the display panel 120, therefore the button member 160 needs to be located at a bottom side of the shield 140 at the flange 147. This means the liquid crystal display 1 is relatively large and heavy, and correspondingly costly.
Accordingly, what is needed is a shield of a liquid crystal display configured to overcome the above-described problems.